In recent years, various disorders and diseases caused by active oxygen species such as superoxide anion radical (O.sub.2.sup.-), hydroxyl radical (.OH), singlet oxygen (.sup.1 O.sub.2), and peroxide lipid have been reported. It is known that active oxygen species are deeply implicated as a cause in aging, canceration, pigmentation, inflammation or other skin disorders induced by the solar rays, particularly UV rays. The implication of active oxygen species in disorders and diseases in living bodies other than skin has also been explained. For example, active oxgen species derived from molecular oxygens added into ischemic tissues by blood reperfusion play an important role in ischemic reperfusion-induced disorders in organs such as heart, enteron, gaster, liver, kidney, and brain. Similarly, active oxygen species generated in living bodies bring about, for example, a wide variety of disorders and diseases such as inflammation, rheumatism, aging, cancer, arteriosclerosis, digestive diseases, kidney diseases, endocrine disorders, lung diseases, shock, disseminated intravascular coagulation syndrome, etc. It has been also reported that active oxygen species are responsible for denaturation and deterioration caused by oxidation of fats and oils in foods.
If the action of active oxygen species in such a wide range including living organs such as skin and foods could be inhibited, these disorders and diseases as well as denaturation and deterioration of foods would be prevented.
Known agents inhibiting the action of active oxygen species include enzyme-based anti-oxydants such as superoxide dismutase (SOD); non-enzyme-based anti-oxydants such as ascorbic acid, tocopherol and glutathione; and vegetable-derived anti-oxydant such as tannin. Recently, some attempts have been reported to inhibit the generation of active oxygen species by capture of metal ions, in view of the fact that metal ions present in living bodies function as catalyst in the generation of active oxygen species (For example, see "Free Radicals in Biology and Medicine", Oxford, Clarendon Press, p. 234, 1989).
Among known agents which inhibit the action of active oxygen species, SOD is limited in use because of its high costs and instability. Many of non-enzyme-based anti-oxydants such as ascorbic acid, tocopherol and glutathione are also instable and insufficient to inhibit the action of active oxygen species. Further, vegetable-derived anti-oxydants such as tannin often suffer from problems of stability, since they are susceptible to hydrolysis, oxydation, etc.
Desferrioxamines are typical compounds capable of capturing metal ions. However, they have so high metal ion capturing capacity for pharmaceutical use that they disturb the balance of metal ions in living bodies and thus invite side effects such as inflammation. Moreover, they have the disadvantage that they can not show sufficient inhibitory effects on the generation of active oxygen species by oral administration. Further, they are difficult to use in cosmetics and foods because of their high costs. Other than desferrioxamines, metal ion chelating agents such as 2,2'-dipyridyl, 1,10-phenanthrolene, and 2,2'-dipyridylamine were examined, but most of them showed toxicity or skin irritation.
An object of this invention is to provide a novel anti-active oxygen agent which inhibits the generation of active oxygen species, ensures a high safety and can be produced at relatively low costs.